This includes the physical routers that handled the data. The traceroute also tells you how much time it took for the data to go from one device to another. Each time data goes between routers, the trip is referred to as a hop. The information revealed by the traceroute can be used to figure out which devices along the route are causing delays. A ping is similar to a traceroute but simpler.

It reports how long it takes for data to go between two points. ICMP is also used to hurt network performance. This is done using an ICMP flood, a Smurf attack, and a ping of death attacks that overwhelms a device on the network and prevent normal functionality. As a result, there is no need for a device to connect with another prior to sending an ICMP message.

For example, in TCP, the two devices that are communicating first engage in a handshake that takes several steps. After the handshake has been completed, the data can be transferred from the sender to the receiver. This information can be observed using a tool like tcpdump. ICMP is different. No connection is formed. The message is simply sent. Also, unlike with TCP and UDP, which dictate the ports to which information is sent, there is nothing in the ICMP message that directs it to a certain port on the device that will receive it.

A ping of death attack involves an attacker sending an extremely large ping to a device that cannot handle pings of that size. The machine may then crash or freeze up. The packet of data is fragmented as it heads toward the target, but during the reassembly process, it is put back together.

When it reaches the target, there is a buffer overflow, causing the device to malfunction. Ping of death attacks are more a danger for older equipment within the network. When the equipment on the network replies, each reply gets sent to the spoofed IP address, and the target is flooded with a ton of ICMP packets. The reply will have a Type of 0. The program times the gap between sending the echo request packet and the arrival of the reply.

The echo request packet is unusual in that it is the only ICMP packet that is sent out without being provoked by an error. Ping has two options that allow you to specify a list of addresses for the path that the transmission should take. See also: Best Ping Sweep Tools. You may wonder which port Ping uses. The answer is: none. If that port is not active, the transmission will provoke an ICMP message from the host of type 3 destination unreachable subtype 3 destination port unreachable.

So, although it is possible to provoke an ICMP message about a port, it is not possible to use the Ping mechanism to send an ICMP packet to that port in the first place as an echo request. If you tack a port number onto the IP address in a Ping command i. Pathping is a utility that is built into the Windows operating system and it is available in all versions since Windows NT. These are the echo request and echo reply message type 8 and 0 and the time exceeded message type As with both Traceroute and Ping , it is possible to give a list of addresses for a suggested path as a parameter to the command and the utility will try to send a packet to the target network via those addresses.

Pathping produces a formatted results report that shows the route and the round trip times to each router. It will send repeated ping requests to each router in the path rather than just repeatedly contacting the destination. That is what Ping does, or just logging each router in the path once, which is what Traceroute does. Pathping is not as resilient as Ping or Traceroute. Some router and server owners intentionally turn off ICMP functions as a protection against hacker attack.

If an intermediate router will not use ICMP, Ping still gets through that router to test the destination. If Traceroute encounters a router that will not send out ICMP packets, it simply progresses to the next router, presenting a line of asterisks for the uncommunicative router.

The main reason that some equipment owners turn the ICMP capabilities of their devices off is that the system can be used by hackers as a conduit for attacks. The Smurf attack is one such case. The Smurf attack uses a reflector strategy. The attacker works out the broadcast address used on the network of the victim and then sends out an ICMP echo request Ping.

Each device on the network will send an echo reply back to the router that hosts that broadcast IP address. This attack only works on large networks. It effectively provokes a Distributed Denial of Service DDoS attack from within the network, whereas most attacks are launched through remote computers over the internet. Some implementations of Ping work better than others. However, this option is not available with all versions of Ping — it is not a valid option on the version that is embedded into Windows , for example.

The fact that the flood option is not universal presents problems for hackers that want to direct remote computers infected with a botnet controlling program to send out the Ping requests. As the flood option is rare, it is probable that most of the devices in the botnet will be unable to launch the attack. This attack strategy would have more success if the hacker ensured that all of the infected computers used an attempt to launch the attack had the flood option available in their Ping implementations.

One way to ensure that would be to test computers before any attack and categorize a group that has the right form of Ping , or to install a flood-enabled Ping on all computers that are infected by the botnet virus. If you are running a web server, then a web application firewall should protect you from Ping floods. The Ping of Death involves sending over-long ping request packets.

The request will have a large amount of filler on the end of it in the payload. The receiver will notice that this is an extra long packet that has been broken up and try to reassemble the original, long packet before sending it on to its destination application.

If the length of the packet is more bytes than the size of available memory in the receiving computer, the attempt to reassemble the packet will jam the computer. Ping of Death is now a well-known attack type and so stateful firewalls and intrusion detection systems can spot it and block it.

As with any hacker trick that becomes known, its effectiveness is no longer threatening. So, hackers have largely dropped the Ping of Death strategy in favor of the Ping flood. So a normal packet with lots of data in it would be passed through just as long as it had an ICMP section in it. This is potentially a backdoor for visitors to get around the authentication and charging procedures of public networks. An ICMP tunnel would have to be programmed.

This is also a possible route into a network for a hacker. Unfortunately, for network administrators, there are a number of free ICMP tunnel packages available for download from the internet. As with the previous two types of ICMP attacks, Ping tunnels can be blocked by web application firewalls, intrusion detection systems, or by simply blocking all ICMP activity at the network gateway.

Twinge is a hacker attack program. It launches an ICMP flood to overwhelm a target computer. Although all of the Ping requests that the target receives seem to have come from many different sources, they are all actually from the same source , each with a fake source IP address in the header.

It uses a data packet structure with an 8-byte header and variable-size data section. How does ICMP work? ICMP is used by a device, like a router, to communicate with the source of a data packet about transmission issues.

For example, if a datagram is not delivered, ICMP might report this back to the host with details to help discern where the transmission went wrong. It's a protocol that believes in direct communication in the workplace. ICMP and Ping. Ping is a utility which uses ICMP messages to report back information on network connectivity and the speed of data relay between a host and a destination computer.

It's one of the few instances where a user can interact directly with ICMP, which typically only functions to allow networked computers to communicate with one another automatically.